Engineering dual-heterogeneous membrane surface with heterostructured modifier to integrate multi-defense antifouling mechanisms

Membrane fouling is one of the main bottlenecks in membrane separation processes for water purification. Due to the complexity of foulants, engineering the membrane surface to coordinate multi-defense mechanisms is essential for fabricating membranes with broad-spectrum antifouling performance. In this study, we synthesized a heterostructured modifier comprising zwitterionic, fluorine-containing polymeric segments and inorganic silver nanoparticles. The heterostructured modifiers were synergistically segregated to the membrane surface during non-solvent induced phase separation. A dual-heterogeneous surface structure was formed, compromising physicochemical heterogeneity with hydrophilic-low surface energy-antibacterial domains, as well as topological heterogeneity with nanopapillae. Consequently, multi-defense mechanisms including passive fouling resistance, fouling release and active antibacterial mechanisms were integrated to the membrane surface, leading to superior antifouling performances against oil-in-water emulsions with ultralow total flux decline ratio of 3.3% and the flux recovery ratio of nearly 100%, as well as nearly 100% antibacterial activity against E. Coli with an obvious inhibition zone.